Speaking at a specially convened roundtable debate in London earlier this week, the group found that while technology – particularly the internet – coped well with the disaster, the main problems came from poor disaster recovery planning.

Experts said that in the aftermath of the carnage, the internet came of age, proving itself as a robust communications utility. Some banks managed to get standby systems going within hours.

But many firms found they were unable to reach their standby sites, because the area was cordoned off or inaccessible, and others found they had too much information held either on paper or on inaccessible desktop PCs.

John Rade, president of AXS-One, a Manhattan-based supplier of financial software to many of the brokerages in the area, summed up the mixed fortunes of those affected. ‘The off-site storage systems worked superbly, and banks and brokerages were able to get their enterprise software up and running quickly – in one case, within four hours,’ he said.

‘But for two weeks they were out of business because people couldn’t get to their screens, even though the technology worked superbly.’

He predicted that companies would start to revise their attitude to working remotely. ‘It’s been regarded as a nice, green thing to do, but now staff distribution has added another dimension to risk planning,’ he said.

Mark Reeves, European vice president of RSA Security, agreed: ‘IT security at the World Trade Center was better than average, but having most of your staff on the 90th floor of a building was a clear risk. The people element is going to play a more important role in security planning from now on.’

The lesson has already been learned by some, according to Andy Palmer, European managing director of Foundry Networks. Investment bank Morgan Stanley, which lost its building and its data centre next to the WTC twin towers, is now looking to spread people and technology more widely.

And Richard Collins, European managing director for storage firm Quantum, questioned why any company would want to site a data centre in a crowded district anyway. ‘It’s crazy to use up expensive office space housing technology,’ he said. He predicted that more data centres will now be housed well away from company offices, linked by high-speed back-up systems.

While the internet provided a means of communication, and some people were able to resume working remotely from their homes, other less technology-savvy people were left stranded, Rade said. Better training is needed, he said, to ensure people have the ability to access systems in different ways.

While some disaster plans worked well, the attacks exposed some serious weaknesses. ‘The penny has finally dropped that information is the most valuable asset of companies,’ said Quantum’s Richard Collins. ‘But much of it was held in people’s heads, on bits of paper, or on desktop PCs. We’ll never know how much information and knowledge has been destroyed forever.’

In one bank, he said, a worker had been managing $1bn worth of business on an Excel spreadsheet with the data held on the PC. The machine was destroyed, with its data, in the attacks.

In the wake of the disaster, Rade said his company had received a request for 832 fax machines from one company. ?That’s ridiculous. We must reduce our dependence on manual systems Ð- its Dickensian,? he said.

But the move to all-electronic trading is still hampered by the fact that in many circumstances, a signed paper document is still required for a legally-binding deal.

As well as forcing companies to review any aspects of their business and IT, the panel agreed the 11 September attacks may have had a beneficial effect on the world economy.

?They [the attacks] have accelerated the recession, but we’ll come out of it faster,? said Roger Bearman of online storage company MTI. Many companies, moved fast to make huge staff cuts within days of 11 September.

The attacks gave them the excuse they needed to take action that was already long overdue, he said.

Quantum’s Collins said it was not so much a recession as a correction, taking companies back to their true values and size after a period of hype and over-expansion.

In cold economic terms, the attacks Ðand the conflict that ensued will be good news for the IT vendors, they said. More than $40bn of equipment was destroyed in the attacks, all of which will need to be replaced.

With governments on both sides of the Atlantic spending more money to finance the Afghan war, the effect will be to revive the flagging economy, all agreed.

The new thinking, post 11 September, will also spark a burst of new technology buying as companies review the way they work. The panel foresaw a rise in demand for data storage and backup systems and services, and a greater focus on trying to capture the knowledge often held in people’s heads.